I would hope a guy would feel more than a "sort of connection" with the mother of his child. However, if you are trying to get a guy to stay with you by having his child, you are in for a world of trouble. Other than the potential for some child support payments, the most you are going to get out of a guy who has no interest in you who is the father of your child and was somehow tricked, is a rocky, awkward and sad lifelong relationship.
If you guys either agreed to the pregnancy or it happened accidentally, he may just feeling a little nervous about the HUGE life change coming, which is totally normal. Unfortunately, he may be having issues with you for other reasons. That's life! If this is the case, as long as he's good to his child, that's the best you can hope for.
I assume the "sort of connection" already occurred, causing the pregnancy. Anthropologically, the child is most likely to resemble the father for the first year of its life, a mechanism which is believed to have been developed as a way of making a connection between the father and son. The mother would have had a 9-month head start on the father, so nature makes it so that if the father sees himself in the child, he will be more likely to stick around. You might have some luck with your baby daddy as a father-figure if you planned this, or even if it is an accident (only less so). If you are scheming to become pregnant in an effort to keep him around, however, GOOD LUCK, because he's more likely to head for the hills than stay with a batty person such as yourself.
Ahhhh, women!! You will be in for a rude awakening. An already established connection has often failed to keep men around let alone one that isn't (it seems the connection is not there and home girl knows it). Don't do yourself in, children are a gift but try and leave that for the couple that want to do this TOGETHER.
Girl, why are you trying to have a kid with someone you're unsure about? Raising a child is hard enough when both parents are on the same page. Having a baby isn't like a Betsy-Wetsy, it's a real live person who will depend on you for nearly two decades. This guy is really going to be pissed off if you trick him into becoming a father.